package com.hmdp.utils;

import cn.hutool.core.lang.UUID;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;

import java.util.Collections;
import java.util.concurrent.TimeUnit;

/**
 * @author 李彬
 * @version 1.0
 */
public class SimpleRedisLock implements ILock{
    private StringRedisTemplate stringRedisTemplate;

    private String name;

    public SimpleRedisLock(StringRedisTemplate stringRedisTemplate, String name) {
        this.stringRedisTemplate = stringRedisTemplate;
        this.name = name;
    }

    private static final String KEY_PREFIX = "lock:";
    private static final String ID_PREEIX = UUID.randomUUID().toString(true) + "-";

    @Override
    public boolean tryLock(long timeoutSec) {
        //获取线程指示
        String threadId =ID_PREEIX + Thread.currentThread().getId();
        //获取锁
        Boolean success = stringRedisTemplate.opsForValue().
                setIfAbsent(KEY_PREFIX + name, threadId , timeoutSec, TimeUnit.SECONDS);
        return Boolean.TRUE.equals(success);
    }

    private static final DefaultRedisScript<Long> UNLOCK_SCRIPT;
    static {
        UNLOCK_SCRIPT = new DefaultRedisScript<>();
        UNLOCK_SCRIPT.setLocation(new ClassPathResource("unlock.lua"));
        UNLOCK_SCRIPT.setResultType(Long.class);
    }
    @Override
    public void unLock() {
        //调用lua脚本
        stringRedisTemplate.execute(
                UNLOCK_SCRIPT,
                Collections.singletonList(KEY_PREFIX + name),
                ID_PREEIX + Thread.currentThread().getId());
    }
}
